Formation of SiOCN thin films

ABSTRACT

Methods for depositing silicon oxycarbonitride (SiOCN) thin films on a substrate in a reaction space are provided. The methods can include at least one plasma enhanced atomic layer deposition (PEALD) cycle including alternately and sequentially contacting the substrate with a silicon precursor and a second reactant that does not include oxygen. In some embodiments the methods allow for the deposition of SiOCN films having improved acid-based wet etch resistance.

BACKGROUND

Field of the Invention

The present disclosure relates generally to the field of semiconductordevice manufacturing and, more particularly, to formation of siliconoxycarbonitride (SiOCN) films having desirable chemical resistanceproperties.

Description of the Related Art

There is increasing need for dielectric materials with relatively lowdielectric constant (k) values and relatively low acid-based wet etchrates. Silicon oxycarbonitride may satisfy certain of theserequirements. Typically, deposition processes for SiOCN requireprecursors comprising halides and/or oxygen plasma.

SUMMARY OF THE INVENTION

In some embodiments plasma enhanced atomic layer deposition (PEALD)processes are provided for forming a silicon oxycarbonitride (SiOCN)thin film on a substrate in a reaction space. In some embodiments aPEALD process may comprise at least one deposition cycle comprisingcontacting a surface of the substrate with a vapor phase siliconprecursor to thereby adsorb a silicon species on the surface of thesubstrate, contacting the adsorbed silicon species with at least onereactive species generated by plasma formed from a gas that does notcomprise oxygen, and optionally repeating the contacting steps until aSiOCN film of a desired thickness has been formed. In some embodimentsthe silicon precursor use in a PEALD process has a formula as in one ofthe following general formulas:(R^(I)O)_(4-x)Si(R^(II)—NH₂)_(x)  (1)

wherein x is an integer from 1 to 4;

R^(I) is independently selected from the group consisting of alkyl; and

R^(II) is an independently selected hydrocarbon;(R^(I)O)₃Si—R^(II)—NH₂  (2)

wherein R^(I) is independently selected from the group consisting ofalkyl; and

R^(II) is an independently selected hydrocarbon; and(R^(I)O)_(4-x)Si(—[CH₂]_(n)—NH₂)_(x)  (3)

wherein x is an integer from 1 to 4;

n is an integer from 1-5; and

R^(I) is independently selected from the group consisting of alkyl.

In some embodiments a ratio of a wet etch rate of the SiOCN thin film toa wet etch rate of thermal silicon oxide may be less than about 5. Insome embodiments a ratio of a wet etch rate of the SiOCN thin film to awet etch rate of thermal silicon oxide may be less than about 0.3. Insome embodiments a ratio of a wet etch rate of the SiOCN thin film to awet etch rate of thermal silicon oxide may be less than about 0.1.

In some embodiments the SiOCN thin film may be deposited on athree-dimensional structure on the substrate. In some embodiments a wetetch rate ratio of a wet etch rate of SiOCN formed on a top surface ofthe three-dimensional structure to a wet etch rate of the SiOCN formedon a sidewall surface of the three-dimensional structure may be about1:1 in dilute HF.

In some embodiments the vapor phase silicon precursor may not comprise ahalogen. In some embodiments the silicon precursor may comprise(3-aminopropyl)trimethoxysilane (APTMS). In some embodiments thereactive species may comprise hydrogen plasma, hydrogen atoms, hydrogenradicals, or hydrogen ions. In some embodiments the reactive species maybe generated from a second reactant comprising a noble gas. In someembodiments the reactive species may further comprise nitrogen plasma,nitrogen atoms, nitrogen radicals, or nitrogen ions. In some embodimentsthe reactive species may be generated by plasma from a second reactantcomprising hydrogen. In some embodiments the second reactant maycomprise H₂.

In some embodiments the SiOCN thin film may comprise at least 20 at %oxygen. In some embodiments the SiOCN thin film may comprise at least 5at % carbon. In some embodiments the SiOCN thin film may comprise atleast 5 at % nitrogen.

In some embodiments processes are provided for forming a siliconoxycarbonitride (SiOCN) thin film on a substrate in a reaction space. Insome embodiments a process may comprise a plurality of depositioncycles, at least one deposition cycle may comprise alternately andsequentially contacting a surface of the substrate with a siliconprecursor and a second reactant comprising at least one reactivespecies. In some embodiments a deposition cycle may be repeated two ormore times to form the SiOCN thin film. In some embodiments the siliconprecursor may have a general formula:L_(n)Si(OR^(I))_(4-x-y-z-n)(R^(II)NR^(III)R^(IV))_(x)H_(y)(OH)_(z)

wherein n is an integer from 0 to 3, x is an integer from 1 to 4, y isan integer from 0 to 3, z is an integer from 0 to 3; and 4-x-y-z-n isfrom 0 to 3;

R^(I) is independently selected from the group consisting of alkyl;

R^(II) is an independently hydrocarbon;

R^(III) and R^(IV) are independently selected from the group consistingof alkyl and hydrogen; and

L is independently selected from the group consisting of alkyl andhalogens.

In some embodiments the at least one reactive species may be generatedby plasma formed from a gas that does not comprise oxygen.

In some embodiments the silicon precursor may have a general formula:L_(n)Si(OR^(I))_(4-x-n)(R^(II)NR^(III)R^(IV))_(x)

wherein n is an integer from 0 to 3, x is an integer from 1 to 3;

L is independently selected from the group consisting of alkyl andhalogens;

R^(I) is independently selected from the group consisting of alkyl;

R^(II) is an independently selected hydrocarbon; and

R^(III) and R^(IV) are independently selected from the group consistingof alkyl and hydrogen.

In some embodiments the silicon precursor may have a general formula:Si(OR^(I))_(4-x-y-z)(R^(II)NR^(III)R^(IV))_(x)H_(y)(OH)_(z)

wherein x is an integer from 1 to 4, y is an integer from 0 to 3, z isan integer from 0 to 3;

R^(I) is independently selected from the group consisting of alkyl;

R^(II) is an independently selected hydrocarbon; and

R^(III) and R^(IV) are independently selected from the group consistingof alkyl and hydrogen.

In some embodiments the silicon precursor may have a general formula:Si(OR^(I))_(4-x)(R^(II)NR^(III)R^(IV))_(x)

wherein x is an integer from 1 to 4;

R^(I) is independently selected from the group consisting of alkyl;

R^(II) is an independently selected hydrocarbon; and

R^(III) and R^(IV) are independently selected from the group consistingof alkyl and hydrogen.

In some embodiments the silicon precursor may comprise APTMS. In someembodiments at least one deposition cycle may be a PEALD cycle. In someembodiments a reactive species may be generated by applying RF power offrom about 100 Watts (W) to about 1000 W to the second reactant. In someembodiments a deposition cycle may be carried out at a processtemperature of about 300° C. to about 400° C. In some embodiments thedeposition cycle may be carried out at a process temperature of lessthan about 100° C. In some embodiments the substrate may comprise anorganic material.

In some embodiments processes are provided for depositing a siliconoxycarbonitride (SiOCN) thin film on a substrate in a reaction space. Insome embodiments such a process may comprise contacting a surface of thesubstrate with a silicon precursor comprising at least one ligand bondedthrough carbon to a silicon atom and containing an NH₂-group attached toa carbon chain and at least one ligand bonded to the silicon atomthrough an oxygen atom and in which an alkyl group is bonded to theoxygen atom. In some embodiments a process may further comprise exposingthe substrate to a purge gas and/or vacuum to remove excess titaniumreactant and reaction byproducts, if any, contacting a surface of thesubstrate with a second reactant comprising hydrogen, wherein the secondreactant comprises at least one reactive species generated by plasma,exposing the substrate to a purge gas and/or vacuum to remove excesssecond reactant and reaction byproducts, if any, and repeating thecontacting steps until a SiOCN thin film of desired thickness has beenformed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a process flow diagram for depositing a siliconoxycarbonitride (SiOCN) thin film by a plasma enhanced atomic layerdeposition (PEALD) process according to some embodiments of the presentdisclosure.

FIG. 2 illustrates film growth per cycle (GPC), refractive index, andwet etch rate ratio (WERR) as a function of second reactant gas mixtureratio for SiOCN thin films deposited according to some embodiments ofthe present disclosure.

FIG. 3 illustrates etch amount (dHF wet etch) versus etch time forthermal oxide (TOX) and a SiOCN thin film deposited according to someembodiments of the present disclosure.

FIG. 4 is a compositional X-ray photoelectron spectroscopy (XPS) depthprofile for a SiOCN thin film deposited according to some embodiments ofthe present disclosure.

FIGS. 5A-B illustrate transmission electron microscope (TEM) images of aSiOCN thin film deposited according to some embodiments of the presentdisclosure before and after exposure to a 2-minute dHF dip.

FIGS. 5C-D illustrate transmission electron microscope (TEM) images of aSiOCN thin film deposited according to some embodiments of the presentdisclosure before and after exposure to a 2-minute dHF dip.

DETAILED DESCRIPTION

Silicon oxycarbonitride (SiOCN) films have a wide variety ofapplications, as will be apparent to the skilled artisan, for example inintegrated circuit fabrication. More specifically, SiOCN films thatdisplay a low etch rate have a wide variety of application, both in thesemiconductor industry and outside of the semiconductor industry. SiOCNfilms may be useful as, for example, etch stop layers, sacrificiallayers, low-k spacers, anti-reflection layers (ARL), and passivationlayers.

According to some embodiments of the present disclosure, various SiOCNfilms, precursors, and methods for depositing said films are provided.In some embodiments the SiOCN films have a relatively low wet etch rate,for example in dHF.

In some embodiments SiOCN thin films are deposited on a substrate byplasma-enhanced atomic layer deposition (PEALD) processes. In someembodiments SiOCN thin films are not deposited by liquid phase methods.In some embodiments a SiOCN thin film is deposited over a threedimensional structure, such as a fin in the formation of a finFETdevice.

The formula of the silicon oxycarbonitride films is generally referredto herein as SiOCN for convenience and simplicity. As used herein, SiOCNis not intended to limit, restrict, or define the bonding or chemicalstate, for example the oxidation state of any of Si, O, C, N, and/or anyother element in the film. Further, in some embodiments SiOCN thin filmsmay comprise one or more elements in addition to Si, O, C, and/or N. Insome embodiments the SiOCN films may comprise Si—C bonds, Si—O bonds,and/or Si—N bonds. In some embodiments the SiOCN films may comprise Si—Cbonds and Si—O bonds and may not comprise Si—N bonds. In someembodiments the SiOCN films may comprise more Si—O bonds than Si—Cbonds, for example a ratio of Si—O bonds to Si—C bonds may be from about1:1 to about 10:1. In some embodiments the SiOCN films may comprise fromabout 0% to about 10% nitrogen on an atomic basis (at %). In someembodiments the SiOCN may comprise from about 0% to about 30% carbon onan atomic basis. In some embodiments the SiOCN films may comprise fromabout 0% to about 60% oxygen on an atomic basis. In some embodiments theSiOCN films may comprise about 0% to about 50% silicon on an atomicbasis.

ALD-type processes are based on controlled, generally self-limitingsurface reactions. Gas phase reactions are typically avoided bycontacting the substrate alternately and sequentially with thereactants. Vapor phase reactants are separated from each other in thereaction chamber, for example, by removing excess reactants and/orreactant byproducts between reactant pulses. The reactants may beremoved from proximity with the substrate surface with the aid of apurge gas and/or vacuum. In some embodiments excess reactants and/orreactant byproducts are removed from the reaction space by purging, forexample with an inert gas.

In some embodiments, plasma enhanced ALD (PEALD) processes are used todeposit SiOCN films. In some embodiments PEALD processes as describedherein do not comprise oxygen plasma. Briefly, a substrate or workpieceis placed in a reaction chamber and subjected to alternately repeatedsurface reactions. In some embodiments, thin SiOCN films are formed byrepetition of a self-limiting ALD cycle. In some embodiments, forforming SiOCN films, each ALD cycle comprises at least two distinctphases. The contacting and removal of a reactant from the substrate maybe considered a phase. In a first phase, a vapor phase first reactantcomprising silicon contacts the substrate and forms no more than aboutone monolayer on the substrate surface. This reactant is also referredto herein as “the silicon precursor,” “silicon-containing precursor,” or“silicon reactant” and may be, for example,(3-Aminopropyl)trimethoxysilane (APTMS).

In a second phase, a second reactant comprising a reactive speciescontacts the substrate and may convert adsorbed silicon to SiOCN. Insome embodiments the second reactant comprises a hydrogen precursor. Insome embodiments, the reactive species comprises an excited species. Insome embodiments the second reactant comprises a species from a hydrogencontaining plasma. In some embodiments, the second reactant compriseshydrogen radicals, hydrogen atoms and/or hydrogen plasma. The secondreactant may comprise other species that are not hydrogen precursors. Insome embodiments, the second reactant may comprise a plasma of nitrogen,radicals of nitrogen, or atomic nitrogen in one form or another. In someembodiments, the second reactant may comprise a species from a noblegas, such as He, Ne, Ar, Kr, or Xe, for example as radicals, in plasmaform, or in elemental form. These reactive species from noble gases donot necessarily contribute material to the deposited film, but can insome circumstances contribute to film growth as well as help in theformation and ignition of plasma. In some embodiments a gas that is usedto form a plasma may flow constantly throughout the deposition processbut only be activated intermittently. In some embodiments a gas that isused to form a plasma does not comprise oxygen. In some embodiments theadsorbed silicon precursor is not contacted with a reactive speciesgenerated by a plasma from oxygen. In some embodiments a second reactantcomprising reactive species is generated in a gas that does not compriseoxygen. For example in some embodiments a second reactant may comprise aplasma generated in a gas that does not comprise oxygen. In someembodiments the second reactant may be generated in a gas comprisingless than about 1 atomic % (at %) oxygen, less than about 0.1 at %oxygen, less than about 0.01 at % oxygen, or less than about 0.001 at %oxygen.

Additional phases may be added and phases may be removed as desired toadjust the composition of the final film.

One or more of the reactants may be provided with the aid of a carriergas, such as Ar or He. In some embodiments the silicon precursor and thesecond reactant are provided with the aid of a carrier gas.

In some embodiments, two of the phases may overlap, or be combined. Forexample, the silicon precursor and the second reactant may be contactthe substrate simultaneously in phases that partially or completelyoverlap. In addition, although referred to as the first and secondphases, and the first and second reactants, the order of the phases maybe varied, and an ALD cycle may begin with any one of the phases. Thatis, unless specified otherwise, the reactants can contact the substratein any order, and the process may begin with any of the reactants.

As discussed in more detail below, in some embodiments for depositing aSiOCN film, one or more deposition cycles begin by contacting thesubstrate with the silicon precursor, followed by the second precursor.In other embodiments deposition may begin by contacting the substratewith the second precursor, followed by the silicon precursor.

In some embodiments the substrate on which deposition is desired, suchas a semiconductor workpiece, is loaded into a reaction space orreactor. The reactor may be part of a cluster tool in which a variety ofdifferent processes in the formation of an integrated circuit arecarried out. In some embodiments a flow-type reactor is utilized. Insome embodiments a shower head type of reactor is utilized. In someembodiments, a space divided reactor is utilized. In some embodiments ahigh-volume manufacturing-capable single wafer ALD reactor is used. Inother embodiments a batch reactor comprising multiple substrates isused. For embodiments in which batch ALD reactors are used, the numberof substrates is in the range of 10 to 200, in the range of 50 to 150,or in the range of 100 to 130.

Examples of suitable reactors that may be used include commerciallyavailable equipment such as the F-120® reactor, F-450® reactor, Pulsar®reactors—such as the Pulsar® 2000 and the Pulsar® 3000—EmerALD® reactorand Advance® 400 Series reactors, available from ASM America, Inc ofPhoenix, Ariz. and ASM Europe B.V., Almere, Netherlands. Othercommercially available reactors include those from ASM Japan K.K (Tokyo,Japan) under the tradename Eagle® XP and XP8.

In some embodiments, if necessary, the exposed surfaces of the workpiececan be pretreated to provide reactive sites to react with the firstphase of the ALD process. In some embodiments a separate pretreatmentstep is not required. In some embodiments the substrate is pretreated toprovide a desired surface termination. In some embodiments the substrateis pretreated with plasma.

Excess reactant and reaction byproducts, if any, are removed from thevicinity of the substrate, and in particular from the substrate surface,between reactant contacting phases. In some embodiments excess reactantand reaction byproducts, if any, are removed from the substrate surfaceby, for example, purging the reaction chamber between reactantcontacting phases, such as by purging with an inert gas. The flow rateand contacting time of each reactant is tunable, as is the removal step,allowing for control of the quality and various properties of the films.

As mentioned above, in some embodiments a gas is provided to thereaction chamber continuously during each deposition cycle, or duringthe entire ALD process, and reactive species are provided by generatinga plasma in the gas, either in the reaction chamber or upstream of thereaction chamber. In some embodiments the gas comprises nitrogen. Insome embodiments the gas is nitrogen. In some embodiments the gas maycomprise noble gas, such as helium or argon. In some embodiments the gasis helium or nitrogen. The flowing gas may also serve as a purge gas forthe first and/or second reactant (or reactive species). For example,flowing nitrogen may serve as a purge gas for a first silicon precursorand also serve as a second reactant (as a source of reactive species).In some embodiments, nitrogen, argon, or helium may serve as a purge gasfor a first precursor and a source of excited species for converting thesilicon precursor to the SiOCN film. In some embodiments the gas inwhich the plasma is generated does not comprise nitrogen and theadsorbed silicon precursor is not contacted with a reactive speciesgenerated by a plasma from nitrogen. In some embodiments the gas inwhich the plasma is generated does not comprise oxygen and the adsorbedsilicon precursor is not contacted with a reactive species generated bya plasma from oxygen.

The cycle is repeated until a film of the desired thickness andcomposition is obtained. In some embodiments the deposition parameters,such as the precursor flow rate, contacting time, removal time, and/orreactants themselves, may be varied in one or more deposition cyclesduring the ALD process in order to obtain a film with the desiredcharacteristics.

In some embodiments the surface of the substrate is contacted with areactant. In some embodiments a pulse of reactant is provided to areaction space containing the substrate. The term “pulse” may beunderstood to comprise feeding reactant into the reaction chamber for apredetermined amount of time. The term “pulse” does not restrict thelength or duration of the pulse and a pulse can be any length of time.In some embodiments the substrate is moved to a reaction spacecontaining a reactant. In some embodiments the substrate is subsequentlymoved from a reaction space containing a first reactant to a second,different reaction space containing the second reactant.

In some embodiments, the substrate is contacted with the siliconreactant first. After an initial surface termination, if necessary ordesired, the substrate is contacted with a first silicon reactant. Insome embodiments a first silicon reactant pulse is supplied to theworkpiece. In accordance with some embodiments, the first reactant pulsecomprises a carrier gas flow and a volatile silicon species, such asAPTMS, that is reactive with the workpiece surfaces of interest.Accordingly, the silicon reactant adsorbs upon these workpiece surfaces.The first reactant pulse self-saturates the workpiece surfaces such thatany excess constituents of the first reactant pulse do not further reactwith the molecular layer formed by this process.

The first silicon reactant pulse can be supplied in gaseous form. Thesilicon precursor gas is considered “volatile” for purposes of thepresent description if the species exhibits sufficient vapor pressureunder the process conditions to transport the species to the workpiecein sufficient concentration to saturate exposed surfaces.

In some embodiments the silicon reactant contacts the surface from about0.05 seconds to about 5.0 seconds, about 0.1 seconds to about 3 secondsor about 0.2 seconds to about 1.0 seconds. The optimum contacting timecan be readily determined by the skilled artisan based on the particularcircumstances.

After sufficient time for about a molecular layer to adsorb on thesubstrate surface, excess first silicon reactant, and reactionbyproducts, if any, are removed from the substrate surface. In someembodiments removing excess reactant and reaction byproducts, if any,may comprise purging the reaction chamber. In some embodiments thereaction chamber may be purged by stopping the flow of the firstreactant while continuing to flow a carrier gas or purge gas for asufficient time to diffuse or purge excess reactants and reactantbyproducts, if any, from the reaction space. In some embodiments theexcess first precursor is purged with the aid of inert gas, such asnitrogen or argon, which is flowing throughout the ALD cycle. In someembodiments the substrate may be moved from the reaction spacecontaining the first reactant to a second, different reaction space. Insome embodiments, the first reactant is removed for about 0.1 seconds toabout 10 seconds, about 0.3 seconds to about 5 seconds or about 0.3seconds to about 1 second. Contacting and removal of the siliconreactant can be considered the first or silicon phase of the ALD cycle.

In the second phase, a second reactant comprising a reactive species,such as hydrogen plasma is provided to the workpiece. Hydrogen plasmamay be formed by generating a plasma in hydrogen in the reaction chamberor upstream of the reaction chamber, for example by flowing the hydrogen(H₂) through a remote plasma generator.

In some embodiments, plasma is generated in flowing H₂ gas. In someembodiments H₂ is provided to the reaction chamber before the plasma isignited or hydrogen atoms or radicals are formed. In some embodimentsthe H₂ is provided to the reaction chamber continuously and hydrogencontaining plasma, atoms or radicals is created or supplied when needed.

Typically, the second reactant, for example comprising hydrogen plasma,contacts the substrate for about 0.1 seconds to about 10 seconds. Insome embodiments the second reactant, such as hydrogen containingplasma, contacts the substrate for about 0.1 seconds to about 10seconds, 0.5 seconds to about 5 seconds or 0.5 seconds to about 2.0seconds. However, depending on the reactor type, substrate type and itssurface area, the second reactant contacting time may be even higherthan about 10 seconds. In some embodiments, contacting times can be onthe order of minutes. The optimum contacting time can be readilydetermined by the skilled artisan based on the particular circumstances.

In some embodiments the second reactant is provided in two or moredistinct pulses, without introducing another reactant in between any ofthe two or more pulses. For example, in some embodiments a plasma, suchas a hydrogen containing plasma, is provided in two or more sequentialpulses, without introducing a Si-precursor in between the sequentialpulses. In some embodiments during provision of plasma two or moresequential plasma pulses are generated by providing a plasma dischargefor a first period of time, extinguishing the plasma discharge for asecond period of time, for example from about 0.1 seconds to about 10seconds, from about 0.5 seconds to about 5 seconds or about 1.0 secondsto about 4.0 seconds, and exciting it again for a third period of timebefore introduction of another precursor or a removal step, such asbefore the Si-precursor or a purge step. Additional pulses of plasma canbe introduced in the same way. In some embodiments a plasma is ignitedfor an equivalent period of time in each of the pulses.

In some embodiments plasma, for example hydrogen containing plasma maybe generated by applying RF power of from about 10 W to about 2000 W,from about 50 W to about 1000 W, or from about 100 W to about 500 W insome embodiments. In some embodiments, a plasma power used forgenerating a nitrogen-containing plasma can be about 500 W to about1,500 W, 700 W to about 1200 W or about 800 W to about 1,000 W. In someembodiments the RF power density may be from about 0.02 W/cm² to about2.0 W/cm², or from about 0.05 W/cm² to about 1.5 W/cm². The RF power maybe applied to second reactant that flows during the plasma contactingtime, that flows continuously through the reaction chamber, and/or thatflows through a remote plasma generator. Thus in some embodiments theplasma is generated in situ, while in other embodiments the plasma isgenerated remotely. In some embodiments a showerhead reactor is utilizedand plasma is generated between a susceptor (on top of which thesubstrate is located) and a showerhead plate. In some embodiments thegap between the susceptor and showerhead plate is from about 0.1 cm toabout 20 cm, from about 0.5 cm to about 5 cm, or from about 0.8 cm toabout 3.0 cm.

After a time period sufficient to completely saturate and react thepreviously adsorbed molecular layer with the plasma pulse, any excessreactant and reaction byproducts are removed from the substrate surface.

In some embodiments removing excess reactant and reaction byproducts, ifany, may comprise purging the reaction chamber. In some embodiments thereaction chamber may be purged by stopping the flow of the secondreactant while continuing to flow a carrier gas or purge gas for asufficient time to diffuse or purge excess reactants and reactantbyproducts, if any, from the reaction space. In some embodiments theexcess second precursor is purged with the aid of inert gas, such asnitrogen or argon, which is flowing throughout the ALD cycle. In someembodiments the substrate may be moved from the reaction spacecontaining the second reactant to a different reaction space. Theremoval may, in some embodiments, be from about 0.1 seconds to about 10seconds, about 0.1 seconds to about 4 seconds or about 0.1 seconds toabout 0.5 seconds. Together, the reactive species contacting and removalrepresent a second, reactive species phase in a SiOCN atomic layerdeposition cycle.

The two phases together represent one ALD cycle, which is repeated toform SiOCN thin films of a desired thickness. While the ALD cycle isgenerally referred to herein as beginning with the silicon phase, it iscontemplated that in other embodiments the cycle may begin with thereactive species phase. One of skill in the art will recognize that thefirst precursor phase generally reacts with the termination left by thelast phase in the previous cycle. Thus, while no reactant may bepreviously adsorbed on the substrate surface or present in the reactionspace if the reactive species phase is the first phase in the first ALDcycle, in subsequent cycles the reactive species phase will effectivelyfollow the silicon phase. In some embodiments one or more different ALDcycles are provided in the deposition process.

According to some embodiments of the present disclosure, PEALD reactionsmay be performed at temperatures ranging from about 25° C. to about 700°C., from about 50° C. to about 600° C., from about 100° C. to about 450°C., or from about 200° C. to about 400° C. In some embodiments, theoptimum reactor temperature may be limited by the maximum allowedthermal budget. Therefore, in some embodiments the reaction temperatureis from about 300° C. to about 400° C. In some applications, the maximumtemperature is around about 400° C., and, therefore the PEALD process isrun at that reaction temperature.

The substrate on which a thin film is deposited may comprise varioustypes of materials. In some embodiments the substrate may comprise anintegrated circuit workpiece. In some embodiments the substrate maycomprise silicon. In some embodiments the substrate may comprise siliconoxide, for example, thermal oxide. In some embodiments the substrate maycomprise a high-k dielectric material. In some embodiments the substratemay comprise carbon. For example the substrate may comprise an amorphouscarbon layer, graphene, and/or carbon nanotubes.

In some embodiments the substrate may comprise a metal, including, butnot limited to W, Cu, Ni, Co, and/or Al. In some embodiments thesubstrate may comprise a metal nitride, including, but not limited toTiN and/or TaN. In some embodiments the substrate may comprise a metalcarbide, including, but not limited to TiC and/or TaC. In someembodiments the substrate may comprise a metal chalcogenide, including,but not limited to MoS₂, Sb₂Te₃, and/or GeTe. In some embodiments thesubstrate may comprise a material that would be oxidized by exposure toan oxygen plasma process, but not by a PEALD process as describedherein.

In some embodiments a substrate used in the PEALD processes describedherein may comprise an organic material. For example, the substrate maycomprise an organic material such as a plastic, polymer, and/orphotoresist. In some embodiments where the substrate comprises anorganic material the reaction temperature of a PEALD process may be lessthan about 200° C. In some embodiments the reaction temperature may beless than about 150° C., less than about 100° C., less than about 75°C., or less than about 50° C.

In some embodiments where a substrate comprises an organic material themaximum process temperature may be as low as 100° C. In some embodimentswhere the substrate comprises an organic material, the absence of aplasma generated from oxygen may allow for deposition of a SiOCN thinfilm on an organic material that may not otherwise degrade in adeposition process including plasma generated from oxygen.

According to some embodiments of the present disclosure, the pressure ofthe reaction chamber during processing is maintained at from about 0.01Torr to about 50 Torr, or from about 0.1 Torr to about 10 Torr. In someembodiments the pressure of the reaction chamber is greater than about 6Torr, or about 20 Torr. In some embodiments, a SiOCN deposition processcan be performed at a pressure of about 20 Torr to about 500 Torr, about20 Torr to about 50 Torr, or about 20 Torr to about 30 Torr.

In some embodiments a SiOCN deposition process can comprise a pluralityof deposition cycles, wherein at least one deposition cycle is performedin an elevated pressure regime. For example, a deposition cycle of aPEALD process may comprise alternately and sequentially contacting thesubstrate with a silicon precursor and a second reactant under theelevated pressure. In some embodiments, one or more deposition cycles ofthe PEALD process can be performed at a process pressure of about 6 Torrto about 500 Torr, about 6 Torr to about 50 Torr, or about 6 Torr toabout 100 Torr. In some embodiments, the one or more deposition cyclescan be performed at a process pressure of greater than about 20 Torr,including about 20 Torr to about 500 Torr, about 30 Torr to about 500Torr, about 40 Torr to about 500 Torr, or about 50 Torr to about 500Torr. In some embodiments, the one or more deposition cycles can beperformed at a process pressure of about 20 Torr to about 30 Torr, about20 Torr to about 100 Torr, about 30 Torr to about 100 Torr, about 40Torr to about 100 Torr or about 50 Torr to about 100 Torr.

PEALD of SiOCN

As mentioned above, and discussed in more detail below, in someembodiments SiOCN thin films can be deposited on a substrate in areaction space by a plasma enhanced atomic deposition layer (PEALD)process. According to some embodiments, a SiOCN thin film is depositedusing a PEALD process on a substrate having three-dimensional features,such as in a FinFET application. In some embodiments a PEALD process asdescribed herein may be used in a variety of applications. For example,a PEALD process as described herein may be used in the formation ofhardmask layers, sacrificial layers, protective layers, or low-kspacers. A PEALD process as described herein may be used in, forexample, memory device applications.

In some embodiments a SiOCN thin film may be deposited by a PEALDprocess as described herein on a substrate that is not able to withstandO plasma without damage, for example a substrate comprising an organicand/or photoresist material.

Referring to FIG. 1 and according to some embodiments a SiOCN thin filmis deposited on a substrate in a reaction space by a PEALD depositionprocess 100 comprising at least one cycle comprising:

contacting the substrate with a vapor phase silicon-containing precursorat step 120 such that silicon species adsorb onto the surface of thesubstrate;

removing excess silicon-containing precursor and reaction byproducts, ifany, from the substrate surface at step 130;

contacting the substrate with a second reactant comprising reactivespecies generated by plasma at step 140, thereby converting the adsorbedsilicon species into SiOCN;

removing excess second reactant and reaction byproducts, if any, fromthe substrate surface at step 150; and

optionally repeating the contacting and removing steps at step 160 toform a SiOCN thin film of a desired thickness and composition.

In some embodiments step 140 may comprise remotely generating or formingplasma or reactive species before contacting the substrate with thesecond reactant.

According to some embodiments a SiOCN plasma enhanced ALD depositioncycle can be used to deposit a SiOCN thin film. In certain embodiments,a SiOCN thin film is formed on a substrate by an ALD-type processcomprising multiple SiOCN deposition cycles, each SiOCN deposition cyclecomprising:

contacting a substrate with a vapor phase silicon reactant such that asilicon compound adsorbs on the substrate surface;

exposing the substrate to a purge gas and/or vacuum;

contacting the substrate with reactive species generated by forming aplasma in a second reactant; and

exposing the substrate to a purge gas and/or vacuum;

optionally repeating the contacting and exposing steps until a SiOCNthin film of a desired thickness and composition is obtained.

In some embodiments the exposing the substrate to a purge gas and/orvacuum steps may comprise continuing the flow of an inert carrier gaswhile stopping the flow of a precursor or reactant. In some embodimentsthe exposing the substrate to a purge gas and/or vacuum steps maycomprise stopping the flow of a precursor and a carrier gas into areaction chamber and evacuating the reaction chamber, for example with avacuum pump. In some embodiments the exposing the substrate to a purgegas and/or vacuum steps may comprise moving the substrate from a firstreaction chamber to a second, different reaction chamber containing apurge gas. In some embodiments the exposing the substrate to a purge gasand/or vacuum steps may comprise moving the substrate from a firstreaction chamber to a second, different reaction chamber under a vacuum.

According to some embodiments a SiOCN thin film is deposited on asubstrate in a reaction space by a PEALD deposition process comprisingat least one cycle comprising:

contacting the substrate with APTMS such that silicon species adsorbonto the surface of the substrate;

removing excess APTMS and reaction byproducts, if any, from thesubstrate surface;

contacting the substrate with a second reactant comprising reactivespecies generated by plasma, wherein the reactive species compriseshydrogen;

removing excess second reactant and reaction byproducts, if any, fromthe substrate surface; and

optionally repeating the contacting and removing steps to form a SiOCNthin film of a desired thickness and composition.

In some embodiments contacting the substrate with a second reactant maycomprise remotely generating or forming plasma or reactive speciesbefore contacting the substrate with the second reactant.

In certain embodiments, a SiOCN thin film is formed on a substrate by anALD-type process comprising multiple SiOCN deposition cycles, each SiOCNdeposition cycle comprising: alternately and sequentially contacting thesubstrate with a first vapor phase silicon precursor and a secondreactant comprising reactive species. In some embodiments the siliconprecursor may comprise APTMS and the second reactive species maycomprise hydrogen.

In some embodiments, the PEALD process is performed at a temperaturebetween about 100° C. to about 650° C., about 100° C. to about 550° C.,about 100° C. to about 450° C., about 200° C. to about 600° C., or atabout 200° C. to about 400° C. In some embodiments the temperature isabout 300° C. In some embodiments, for example where a substratecomprises an organic material such as an organic photoresist, the PEALDprocess may be performed at a temperature less than about 100° C. Insome embodiments the PEALD process is performed at a temperature lessthan about 75° C., or less than about 50° C. In some embodiments aplasma may be generated by applying RF power to the second reactant. TheRF power may be applied to second reactant to thereby generate reactivespecies. In some embodiments the RF power may be applied to the secondreactant that flows continuously through the reaction chamber, and/orthat flows through a remote plasma generator. Thus in some embodimentsthe plasma is generated in situ, while in other embodiments the plasmais generated remotely. In some embodiments the RF power applied to thesecond reactant is from about 10 W to about 2000 W, from about 100 W toabout 1000 W or from about 200 W to about 500 W. In some embodiments theRF power applied to the second reactant is about 200 W. In someembodiments, a plasma power used for generating a nitrogen-containingplasma can be about 500 W to about 1500 W, about 800 W to about 1200 W.

As discussed in more detail below, in some embodiments for depositing aSiOCN film, one or more PEALD deposition cycles begin with provision ofthe silicon precursor, followed by the second reactant. In otherembodiments deposition may begin with provision of the second reactant,followed by the silicon precursor. One of skill in the art willrecognize that the first precursor phase generally reacts with thetermination left by the last phase in the previous cycle. Thus, while noreactant may be previously adsorbed on the substrate surface or presentin the reaction space if the reactive species phase is the first phasein the first PEALD cycle, in subsequent PEALD cycles the reactivespecies phase will effectively follow the silicon phase. In someembodiments one or more different PEALD sub-cycles are provided in theprocess for forming a SiOCN thin film.

Si Precursors

A number of different suitable Si precursors can be used in thepresently disclosed PEALD processes. In some embodiments, at least someSi precursors suitable for deposition of SiOCN by PEALD processes havethe following general formula:Si(OR^(I))_(4-x)(R^(II)NR^(III)R^(IV))_(x)  (1)

Wherein x=1-4, R^(I) may be an independently selected alkyl group,R^(II) may be an independently selected hydrocarbon group, and R^(III)and R^(IV) may be independently selected alkyl groups and/or hydrogens.In some embodiments R^(I) and R^(II) are C₁-C₃ alkyl ligands, such asmethyl, ethyl, n-propyl, or isopropyl. In some embodiments R^(I) may bea C₁-C₄ alkyl ligand, such as methyl, ethyl, n-propyl, isopropyl, ortertbutyl. In some embodiments R^(II) is not a C₃ hydrocarbon. In someembodiments R^(II) is a C₁-C₂ hydrocarbon or a C₄-C₆ hydrocarbon. Insome embodiments R^(II) may be an unsaturated hydrocarbon, such as ahydrocarbon containing one or more double bonds. In some embodimentsR^(II) may be an alkyl group where one of the hydrogens is removed. Insome embodiments R^(III) and R^(IV) are hydrogen. In some embodimentsR^(I) is methyl, R^(II) is n-propyl, R^(III) is hydrogen, R^(IV) ishydrogen, and x=1.

For example, an Si precursor may have the formula (written in a moredetailed manner in order to show bonding):(R^(I)—O—)_(4-x)Si(—R^(II)—NR^(III)—R^(IV))x, wherein x=1-4, R¹ may bean independently selected alkyl group, R^(II) may be an independentlyselected hydrocarbon, and R^(III) and R^(IV) may be independentlyselected alkyl groups and/or hydrogens.

According to some embodiments, some Si precursors may have the followinggeneral formula:Si(OR^(I))_(4-x-y-z)(RN^(II)NR^(III)R^(IV))_(x)H_(y)(OH)_(z)  (2)

wherein x=1-4, y=0-3, and z=0-3, R^(I) and R^(II) may be anindependently selected alkyl group, R^(II) may be an independentlyselected hydrocarbon, and R^(III) and R^(IV) may be independentlyselected alkyl groups and/or hydrogens. In some embodiments R^(II) maybe an unsaturated hydrocarbon, such as a hydrocarbon containing one ormore double bonds. In some embodiments R^(II) may be an alkyl groupwhere one of the hydrogens is removed.

According to some embodiments, some Si precursors may have the followinggeneral formula:L_(n)Si(OR^(I))_(4-x-n)(R^(II)NR^(III)R^(IV))_(x)  (3)

wherein n=1-3, x=0-3, R^(I) may be an independently selected alkylgroup, R^(II) may be an independently selected hydrocarbon, and R^(III)and R^(IV) may be independently selected alkyl groups and/or hydrogens,and L is an independently selected alkyl group or halogen. In someembodiments R^(II) may be an unsaturated hydrocarbon, such as ahydrocarbon containing one or more double bonds. In some embodimentsR^(II) may be an alkyl group where one of the hydrogens is removed.

According to some embodiments, some Si precursors may have the followinggeneral formula:L_(n)Si(OR^(I))_(4-x-y-z-n)(R^(II)NR^(III)R^(IV))_(x)H_(y)(OH)_(z)  (4)

wherein n=0-3 x=1-4, y=0-3, z=0-3, R^(I) may be an independentlyselected alkyl group, R^(II) may be an independently selectedhydrocarbon, and R^(III) and R^(IV) may be independently selected alkylgroups and/or hydrogens, and L is an independently selected alkyl groupor halogen. In some embodiments R^(II) may be an unsaturatedhydrocarbon, such as a hydrocarbon containing one or more double bonds.In some embodiments R^(II) may be an alkyl group where one of thehydrogens is removed.

According to some embodiments, some Si precursors may have the followinggeneral formula:(R^(I)O)_(4-x)Si(R^(II)—NH₂)_(x)  5)

wherein x=1-4, R^(I) may be an independently selected alkyl group, andR^(II) may be an independently selected hydrocarbon. In some embodimentsR^(I) and R^(II) are C₁-C₃ alkyl ligands, such as methyl, ethyl,n-propyl, or isopropyl. In some embodiments R^(I) is methyl, R^(II) isn-propyl and x=1. In some embodiments R^(II) may be an unsaturatedhydrocarbon, such as a hydrocarbon containing one or more double bonds.In some embodiments R^(II) may be an alkyl group where one of thehydrogens is removed.

According to some embodiments, some Si precursors may have the followinggeneral formula:(R^(I)O)₃Si—R^(II)—NH₂  6)

Wherein, R^(I) may be an independently selected alkyl group, and R^(II)may be an independently selected hydrocarbon. In some embodiments R^(I)and R^(II) are C₁-C₃ alkyl ligands, such as methyl, ethyl, n-propyl, orisopropyl. In some embodiments R^(II) may be an unsaturated hydrocarbon,such as a hydrocarbon containing one or more double bonds. In someembodiments R^(II) may be an alkyl group where one of the hydrogens isremoved.

According to some embodiments, some Si precursors may have the followinggeneral formula:(R^(I)O)_(4-x)Si(—[CH₂]_(n)—NH₂)_(x)  7)

wherein x=1-4, n=1-5, and R^(I) may be an independently selected alkylgroup. In some embodiments R^(I) is a C₁-C₄ alkyl ligand, such asmethyl, ethyl, n-propyl, or isopropyl. In some embodiments R^(I) ismethyl, and x=1.

In some embodiments the silicon precursor does not comprise a halogen.In some embodiments the silicon precursor may comprise at least oneaminoalkyl ligand. According to some embodiments a suitable siliconprecursor may comprise at least one ligand which is bonded throughcarbon to silicon and contains at least one NH₂-group attached to acarbon chain, for example an aminoalkyl ligand. According to someembodiments a suitable silicon precursor may comprise at least oneligand which is bonded through carbon to silicon and contains anNH₂-group attached to a carbon chain, for example an aminoalkyl ligand,and may also comprise at least one ligand which is bonded to siliconthrough an oxygen atom and in which an alkyl group is bonded to oxygen,for example an alkoxide ligand. According to some embodiments a suitablesilicon precursor may comprise at least one ligand which is bondedthrough carbon to silicon and contains at least oneNR^(III)R^(IV)-group, wherein R^(III) and R^(IV) may be independentlyselected alkyl groups and/or hydrogens, attached to a carbon chain, forexample an aminoalkyl ligand. According to some embodiments a suitablesilicon precursor may comprise at least one ligand which is bondedthrough carbon to silicon and in which ligand at least one nitrogen isbonded to carbon. Further the one ligand which is bonded through carbonto silicon and in which ligand at least one nitrogen is bonded to carbonmay comprise hydrogen bonded to nitrogen. According to some embodiments,in addition to a ligand which is bonded to silicon through carbon, asuitable silicon precursor may comprise also an alkoxy ligand, such asmethoxy, ethoxy, n-propoxy, i-propoxy or tertbutoxy ligand. According tosome embodiments, including some of the formulas of the above, asuitable silicon precursor comprises a carbon chain which is bonded tosilicon through carbon, and in which there is an amino group, such asalkylamino or —NH₂ group, attached to the carbon chain and the carbonchain is a C1-C6 hydrocarbon, C2-C6 hydrocarbon or C2-C4 hydrocarbon,linear, branched or cyclic, containing only carbon and hydrogen. In someembodiments the carbon chain may be unsaturated and contain doublecarbon-carbon bonds. In some other embodiments the carbon chain maycontain other atoms than carbon and hydrogen.

According to some embodiments suitable silicon precursors can include atleast compounds having any of the general formulas (1) through (7). Insome embodiments halides/halogens can include F, Cl, Br, and I. In someembodiments the silicon precursor can comprise(3-aminopropyl)trimethoxysilane (APTMS).

In some embodiments more than one silicon precursor may contact thesubstrate surface at the same time during an ALD phase. In someembodiments the silicon precursor may comprise more than one of thesilicon precursors described herein. In some embodiments a first siliconprecursor is used in a first ALD cycle and a second, different ALDprecursor is used in a later ALD cycle. In some embodiments multiplesilicon precursors may be used during a single ALD phase, for example inorder to optimize certain properties of the deposited SiOCN film. Insome embodiments only one silicon precursor may contact the substrateduring the deposition. In some embodiments there may only be one siliconprecursor and one second reactant or composition of second reactants inthe deposition process. In some embodiments there is no metal precursorin the deposition process. In some embodiments the silicon precursor isnot used as a silylating agent. In some embodiments the depositiontemperature and/or the duration of the silicon precursor contacting stepare selected such that the silicon precursor does not decompose. In someembodiments the silicon precursor may decompose during the siliconprecursor contacting step. In some embodiments the silicon precursordoes not comprise a halogen, such as chlorine or fluorine.

Second Reactants

As discussed above, the second reactant for depositing SiOCN accordingto the present disclosure may comprise a hydrogen precursor, which maycomprise a reactive species. In some embodiments a reactive speciesincludes, but is not limited to, radicals, plasmas, and/or excited atomsor species. Such reactive species may be generated by, for example,plasma discharge, hot-wire, or other suitable methods. In someembodiments the reactive species may be generated remotely from thereaction chamber, for example up-stream from the reaction chamber(“remote plasma”). In some embodiments the reactive species may begenerated in the reaction chamber, in the direct vicinity of thesubstrate, or directly above the substrate (“direct plasma”).

Suitable plasma compositions of a PEALD process include hydrogenreactive species, that is plasma, radicals of hydrogen, or atomichydrogen in one form or another. In some embodiments a second reactantmay comprise a reactive species formed at least in part from H₂. In someembodiments, nitrogen reactive species in the form of plasma, radicalsof nitrogen, or atomic nitrogen in one form or another are alsoprovided. And in some embodiments, a plasma may also contain noblegases, such as He, Ne, Ar, Kr and Xe, or Ar or He, in plasma form, asradicals, or in atomic form. In some embodiments, the second reactantdoes not comprise any species generated from oxygen. Thus, in someembodiments reactive species are not generated from a gas containingoxygen. In some embodiments a second reactant comprising reactivespecies is generated from a gas that does not contain oxygen. Forexample in some embodiments a second reactant may comprise a plasmagenerated from a gas that does not contain oxygen. In some embodimentsthe second reactant may be generated from a gas containing less thanabout 1 atomic % (at %) oxygen, less than about 0.1 at % oxygen, lessthan about 0.01 at % oxygen, or less than about 0.001 at % oxygen. Insome embodiments a second reactant does not comprise O₂, H₂O or O₃.

Thus, in some embodiments the second reactant may comprise reactivespecies formed from compounds having both N and H, such as NH₃ and N₂H₄,a mixture of N₂/H₂ or other precursors having an N—H bond. In someembodiments the second reactant may be formed, at least in part, fromN₂. In some embodiments the second reactant may be formed, at least inpart, from H₂ and N₂, where the H₂ and N₂ are provided at a flow ratio(H₂/N₂), from about 100:1 to about 1:100, from about 20:1 to about 1:20,from about 10:1 to about 1:10, from about 5:1 to about 1:5 and/or fromabout 2:1 to about 4:1, and in some cases 1:1. For example, ahydrogen-containing plasma for depositing SiOCN can be generated usingboth N₂ and H₂ at one or more ratios described herein.

In some embodiments, a hydrogen plasma may be free or substantially freeof nitrogen-containing species (e.g., nitrogen ions, radicals, atomicnitrogen). For example, nitrogen-containing gas is not used to generatethe hydrogen plasma. In some embodiments, nitrogen-containing gas (e.g.,N₂ gas) is not flowed into the reaction chamber during the hydrogenplasma step.

In some embodiments, a hydrogen plasma may be free or substantially freeof oxygen-containing species (e.g., oxygen ions, radicals, atomicoxygen). For example, oxygen-containing gas is not used to generate thehydrogen plasma. In some embodiments, oxygen-containing gas (e.g., O₂gas) is not flowed into the reaction chamber during the hydrogen plasmastep.

In some embodiments, the second reactant does not comprise any speciesgenerated from nitrogen. Thus, in some embodiments reactive species arenot generated from a gas containing nitrogen. In some embodiments asecond reactant comprising reactive species is generated from a gas thatdoes not contain nitrogen. For example in some embodiments a secondreactant may comprise a plasma generated from a gas that does notcontain nitrogen. In some embodiments the second reactant may begenerated from a gas containing less than about 1 atomic % (at %)nitrogen, less than about 0.1 at % nitrogen, less than about 0.01 at %nitrogen, or less than about 0.001 at % nitrogen. In some embodiments asecond reactant does not comprise N₂, NH₃ or N₂H₄.

In some embodiments oxygen-containing gas is not used to generate thehydrogen plasma. In some embodiments, oxygen-containing gas (e.g., O₂gas) is not flowed into the reaction chamber during the hydrogen plasmastep.

In some embodiments the gas used to generated reactive species, such asplasma, may consist essentially of hydrogen. In some embodiments the gasused to generated reactive species, such as plasma, may consistessentially of nitrogen. In some embodiments the gas used to generatedreactive species, such as plasma, may consist essentially of argon oranother noble gas. In some embodiments, a plasma power used forgenerating a hydrogen-containing plasma can be about 10 Watts (W) toabout 2,000 W, about 50 W to about −1000 W, about 100 W to about 1000 Wor about 100 W to about 500 W. In some embodiments, a plasma power usedfor generating a hydrogen-containing plasma can be about 100 W to about300 W.

SiOCN Film Characteristics

SiOCN thin films deposited according to some of the embodimentsdiscussed herein may achieve impurity levels or concentrations belowabout 3 at %, below about 1 at %, below about 0.5 at %, or below about0.1 at %. In some thin films, the total impurity level excludinghydrogen may be below about 5 at %, below about 2 at %, below about 1 at%, or below about 0.2 at %. And in some thin films, hydrogen levels maybe below about 30 at %, below about 20 at %, below about 15 at %, orbelow about 10 at %. As used herein, an impurity may be considered anyelement other than Si, O, C, and/or N.

In some embodiments, the deposited SiOCN films do not comprise anappreciable amount of hydrogen. However, in some embodiments a SiOCNfilm comprising hydrogen is deposited. In some embodiments, thedeposited SiOCN films comprises less than about 30 at %, less than about20 at %, less than about 15 at %, less than about 10 at % or less thanabout 5 at % of hydrogen. In some embodiments the thin films do notcomprise argon.

According to some embodiments, the SiOCN thin films may exhibit stepcoverage and pattern loading effects of greater than about 50%, greaterthan about 80%, greater than about 90%, or greater than about 95%. Insome cases step coverage and pattern loading effects can be greater thanabout 98% and in some case about 100% (within the accuracy of themeasurement tool or method). In some embodiments step coverage andpattern loading effects can be greater than about 100%, greater thanabout 110%, greater than about 120%, greater than about 130%, or greaterthan about 140%. These values can be achieved in features with aspectratios of 2 or greater, in some embodiments in aspect ratios of about 3or greater, in some embodiments in aspect ratios of about 5 or greaterand in some embodiments in aspect ratios of about 8 or greater.

In some embodiments the step coverage may be between about 50% and about110%, between about between about 80% and about 110%, between about 90%and about 110%, between about 95% and 110%, between about 98% and 110%,or between about 100% and 110%. In some embodiments the step coveragemay be between about 50% and about 100%, between about between about 80%and about 100%, between about 90% and about 100%, between about 95% and100%, or between about 98% and 100%.

In some embodiments the growth rate of the film is from about 0.01Å/cycle to about 5 Å/cycle, from about 0.05 Å/cycle to about 2 Å/cycle.In some embodiments the growth rate of the film is more than about 0.05Å/cycle, more than about 0.1 Å/cycle, more than about 0.15 Å/cycle, morethan about 0.3 Å/cycle, more than about 0.3 Å/cycle, more than about 0.4Å/cycle. As used herein, “pattern loading effect” is used in accordancewith its ordinary meaning in this field. While pattern loading effectsmay be seen with respect to impurity content, density, electricalproperties and etch rate, unless indicated otherwise the term patternloading effect when used herein refers to the variation in filmthickness in an area of the substrate where structures are present.Thus, the pattern loading effect can be given as the film thickness inthe sidewall or bottom of a feature inside a three-dimensional structurerelative to the film thickness on the sidewall or bottom of thethree-dimensional structure/feature facing the open field. As usedherein, a 100% pattern loading effect (or a ratio of 1) would representabout a completely uniform film property throughout the substrateregardless of features i.e. in other words there is no pattern loadingeffect (variance in a particular film property, such as thickness, infeatures vs. open field).

In some embodiments, SiOCN films are deposited to a thickness of fromabout 3 nm to about 50 nm, from about 5 nm to about 30 nm, from about 5nm to about 20 nm. These thicknesses can be achieved in feature sizes(width) below about 100 nm, about 50 nm, below about 30 nm, below about20 nm, and in some cases below about 15 nm. According to someembodiments, a SiOCN film is deposited on a three-dimensional structureand the thickness at a sidewall may be slightly even more than 10 nm. Insome embodiments SiOCN films of greater than 50 nm can be deposited. Insome embodiments SiOCN films of greater than 100 nm can be deposited. Insome embodiments, SiOCN films are deposited to a thickness of more thanabout 1 nm, more than about 2 nm, more than about 3 nm, more than about5 nm, more than about 10 nm. According to some embodiments SiOCN filmswith various wet etch rates (WER) may be deposited. When using a blanketWER in 0.5% dHF (nm/min), SiOCN films may have WER values of less thanabout 5, less than about 4, less than about 2, or less than about 1. Insome embodiments SiOCN films may have WER values significantly lessthan 1. In some embodiments SiOCN films may have WER values less thanabout 0.3, less than about 0.2, or less than about 0.1. In someembodiments SiOCN films may have WER values less than about 0.05, lessthan about 0.025, or less than about 0.02.

The blanket WER in 0.5% dHF (nm/min) relative to the WER of thermaloxide may be less than about 3, less than about 2, less than about 1,and less than about 0.5. In some embodiments the blanket WER in 0.5% dHFrelative to the WER of TOX may be less than about 0.1.

In some embodiments wherein a PEALD process is carried out attemperatures less than about 100° C., The blanket WER in 0.5% dHF(nm/min) relative to the WER of thermal oxide may be less than about 10,less than about 5, less than about 3, and less than about 2, or lessthan about 1.

And in some embodiments, the sidewall WER of a three dimensionalfeature, such as a fin or trench relative to the top region WER of athree dimensional feature, such as fin or trench, in 0.5% dHF may beless than about 10, less than about 5, less than about 3, less thanabout 3, or less than about 1. In some embodiments, SiOCN formedaccording to one or more processes described herein can advantageouslydemonstrate a horizontal region to vertical region WERR of about 1, forexample in 0.5% dHF. For example, a ratio of a wet etch rate of SiOCNthin film formed over horizontal surfaces (e.g., top surfaces) to a wetetch rate of the SiOCN thin film formed over vertical surfaces (e.g.,sidewall surfaces) of three-dimensional structures on a substratesurface can be the same or substantially the same. In some embodiments,the ratio can be about 0.25 to about 2, about 0.5 to about 1.5, about0.75 to about 1.25, or about 0.9 to about 1.1. These ratios can beachieved in features with aspect ratios of about 2 or more, about 3 ormore, about 5 or more or even about 8 or more.

In some embodiments, the amount of etching of SiOCN films according tothe present disclosure may be about 1, 2, 5, 10 or more times less thanan amount of etching observed for thermal SiO₂ (TOX) in a 0.5% HF-dipprocess (for example in a process in which about 2 to about 3 nm TOX isremoved, 1, 2, 5, 10 or more times less SiOCN is removed when depositedaccording to the methods disclosed herein).

In some embodiments less than about 2 nm of SiOCN film may be removed ina 0.5% HF-dip process with an etching time of 5 minutes. In someembodiments less than about 2 nm of SiOCN film may be removed in a 0.5%HF-dip process with an etching time of 60 minutes.

All atomic percentage (i.e., at %) values provided herein excludehydrogen for simplicity and because hydrogen is difficult to accuratelyanalyze quantitatively, unless otherwise indicated. However, in someembodiments, if it is possible to analyze the hydrogen with reasonableaccuracy, the hydrogen content of the films is less than about 20 at %,less than about 10 at % or less than about 5 at %. In some embodimentsthe deposited SiOCN thin film may contain up to about 70% oxygen on anatomic basis (at %). In some embodiments a SiOCN film may compriseoxygen from about 10% to about 70%, from about 15% to about 50%, or fromabout 20% to about 40% on an atomic basis. In some embodiments a SiOCNfilm may comprise at least about 20%, about 40% or about 50% oxygen onan atomic basis.

In some embodiments the deposited SiOCN thin film may contain up toabout 40% carbon on an atomic basis (at %). In some embodiments a SiOCNfilm may comprise carbon from about 0.5% to about 40%, from about 1% toabout 30%, or from about 5% to about 20% on an atomic basis. In someembodiments a SiOCN film may comprise at least about 1%, about 10% orabout 20% carbon on an atomic basis.

In some embodiments the deposited SiOCN thin film may contain up toabout 30% nitrogen on an atomic basis (at %). In some embodiments aSiOCN film may comprise nitrogen from about 0.51% to about 30%, fromabout 1% to about 20%, or from about 3% to about 15% on an atomic basis.In some embodiments an SiOCN film may comprise at least about 1%, about5% or about 10% nitrogen on an atomic basis.

In some embodiments the deposited SiOCN thin film may contain up toabout 50% silicon on an atomic basis (at %). In some embodiments a SiOCNfilm may comprise silicon from about 10X % to about 50%, from about 15%to about 40%, or from about 20% to about 35% on an atomic basis. In someembodiments a SiOCN film may comprise at least about 15%, about 20%,about 25% or about 30% silicon on an atomic basis.

In some embodiments the deposited SiOCN thin film may comprise fromabout 30 at % to about 40 at % silicon, from about 25 at % to about 40at % oxygen, from about 10 at % to about 20 at % C, and about 10 at %nitrogen. In some embodiments the deposited SiOCN film may compriseabout 33% silicon and about 67% oxygen. As discussed above, in someembodiments a SiOCN film may comprise Si—C bonds, Si—O bonds, and/orSi—N bonds. In some embodiments a SiOCN film may comprise Si—C bonds andSi—O bonds and may not comprise Si—N bonds. In some embodiments a SiOCNfilm may comprise Si—N bonds and Si—O bonds and may not comprise Si—Cbonds. In some embodiments a SiOCN film may comprise Si—N bonds and Si—Cbonds and may not comprise Si—O bonds. In some embodiments the SiOCNfilms may comprise more Si—O bonds than Si—C bonds, for example a ratioof Si—O bonds to Si—C bonds may be from about 1:1 to about 10:1. In someembodiments a deposited SiOCN film may comprise one or more of SiN, SiO,SiC, SiCN, SiON, and/or SiOC.

In some embodiments a SiOCN film is not a low-k film, for example aSiOCN film is not a porous film. In some embodiments a SiOCN is acontinuous film. In some embodiments a SiOCN film has a k-value that isless than about 10. In some embodiments a SiOCN film has a k-value thatis less than about 7. In some embodiments a SiOCN film has a k-valuesfrom about 3.9 to about 10. In some embodiments a SiOCN film has ak-value that is less than about 5.5, less than about 5.0, less thanabout 4.8, less than about 4.6. In some embodiments a SiOCN film has ak-value that from about 3.8 to about 7, from about 3.8 to about 5.5,from about 3.8 to about 5.0, from about 4.0 to about 4.8, from about 4.1to about 4.7. In some embodiments a SiOCN film has a k-value that ismore than k-value of any low-k film. In some embodiments a SiOCN filmhas a k-value that is more than pure SiO₂.

In some embodiments SiOCN films deposited according to the presentdisclosure do not comprise a laminate or nanolaminate structure.

In some embodiments a SiOCN film deposited according to the presentdisclosure is not a self-assembled monolayer (SAM). In some embodimentsa SiOCN film deposited according to the present disclosure does notconsist of separate, individual molecules which are not bonded to eachother. In some embodiments a SiOCN film deposited according to thepresent disclosure comprises a material which is substantially bonded orlinked together. In some embodiments a SiOCN film deposited according tothe present disclosure is not a functional layer, is notamino-functionalized, and/or is not used as a functional surface. Insome embodiments a SiOCN film deposited according to the presentdisclosure is not terminated with —NH₂ groups. In some embodiments aSiOCN film deposited according to the present disclosure does notcontain a substantial amount of —NH₂ groups.

EXAMPLES

Exemplary SiOCN thin films were deposited by a PEALD process asdescribed herein. The deposition temperature was 300° C. and APTMS wasused as a silicon precursor. A plasma was generated by applying 200 W ofRF power to the second reactant. A mixture of H₂ and N₂ was used as thesecond reactant, which was supplied with an Ar carrier gas. FIG. 2illustrates the growth per cycle (Å/cycle), refractive index, and WERRas compared with TOX as a function of second reactant gas ratio forSiOCN films deposited by a PEALD process as described herein. The secondreactant gas ratio is shown along the X-axis of FIG. 2, and representsthe ratio of N₂ to both H₂ and N₂ (N₂:(H₂+N₂)) in the second reactant.

As can be seen in FIG. 2, the growth rate of the SiOCN films increasedas the N₂:(H₂+N₂) ratio in the second reactant increased. The refractiveindex of the deposited films decreased as the N₂:(H₂+N₂) ratio in thesecond reactant increased. The ratio of the WER of the deposited SiOCNfilms to the WER of TOX (WERR to TOX) was observed to increase as theN₂:(H₂+N₂) ratio in the second reactant increased. Significantly, theWERR to TOX was for SiOCN films deposited with N₂:(H₂+N₂) ratios of 50%and 0% (no N₂ present in the second reactant) was observed to be lessthan 1. Without being bound by any one theory, it is believed that thepresence of H2 in the second reactant results in high wet chemicalresistance in the deposited SiOCN thin film.

FIG. 3 illustrates the etching amount versus etching time for both SiOCNthin films deposited by PEALD processes as described herein and TOX. Theetching process was a 0.5% HF-dip process. As can be seen in FIG. 3, thedeposited SiOCN exhibit significantly greater etch resistance than TOX.After exposure to a 60 minute dip in 0.5% HF less than 2 nm of SiOCNfilm was removed.

The composition of a SiOCN film deposited by a PEALD process asdescribed herein was analysed using X-ray photoelectron spectroscopy(XPS). The deposition temperature was 300° C. and APTMS was used as asilicon precursor. The results are shown in Table 1, below. Two distinctSi bonding energies were identified, indicating the presence of Si—C andSiO bonds in the deposited film.

TABLE 1 Film composition measure by XPS Depth (Å) O N C Si_(SiC)Si_(SiOCN) 0 46.3 5.3 18.6 5.3 24.5 25 41.4 9.0 11.5 6.7 31.5 50 41.58.8 11.0 7.0 31.7 75 41.0 8.9 11.0 5.3 33.8 100 41.9 8.9 10.7 6.3 32.3125 42.0 9.3 10.0 5.9 32.8 150 43.0 8.1 10.7 5.7 32.5 175 43.9 8.3 9.74.7 33.4 200 44.5 8.2 9.0 5.9 32.4 225 45.0 8.3 9.1 5.2 32.4 250 46.07.9 8.4 4.1 33.6 275 47.3 7.5 8.3 5.0 31.8 300 47.8 7.4 7.5 4.6 32.8

FIG. 4 also illustrates film composition as a function depth for anexemplary SiOCN film deposited by a PEALD process as described herein.

FIGS. 5A and 5B are scanning electron microscopy (SEM) images showingcross-section view of SiOCN films formed on trench structure prior toand after exposure to a 2 minutes dip in dHF wet etch solution,respectively. The SiOCN films of FIGS. 5A and 5B were formed accordingto the PEALD processes as described herein. The deposition temperaturewas 300° C. and APTMS was used as a silicon precursor. A plasma wasgenerated by applying 400 W of RF power to the second reactantcomprising H₂. The plasma pulse time was 8 seconds. FIGS. 5C and 5D arescanning electron microscopy (SEM) images showing cross-section view ofSiOCN films formed on trench structure prior to and after exposure to a2 minutes dip in dHF wet etch solution, respectively. The SiOCN films ofFIGS. 5C and 5D were formed according to the PEALD processes asdescribed herein. The deposition temperature was 300° C. and APTMS wasused as a silicon precursor. A plasma was generated by applying 400 W ofRF power to the second reactant comprising H₂ and N₂. The plasma pulsetime was 8 seconds.

As shown in FIGS. 5A and 5C, the SiOCN film formed using a PEALD processwith a second reactant that did not comprise N₂ demonstrated improvedconformaltity prior to the wet etch dip, as compared to the SiOCN filmformed using a PEALD process with a second reactant comprising H₂ andN₂. The SiOCN film formed with a second reactant that did not compriseN₂ had a step coverage of 114% to 136%, while the SiOCN film formed witha second reactant comprising H₂ and N₂ had a step coverage of 54%. Asshown in FIGS. 5B and 5D, the conformality of the SiOCN film formedusing a second reactant that did not comprise N₂ was maintainedsubsequent to the wet etch dip, while that of the SiOCN film formedusing a second reactant comprising H₂ and N₂ was decreased.

Additionally, the SiOCN film formed using a second reactant that did notcomprise N₂ demonstrated a wet etch rate ratio to TOX (WERR to TOX) of0.2 for the horizontal regions of the film and a WERR to TOX of 1.0 forthe vertical regions of the film (sidewall surfaces). The SiOCN filmformed using a second reactant comprising H₂ and N₂ demonstrated a wetetch rate ratio to TOX (WERR to TOX) of 2.0 for the horizontal regionsof the film deposited on top of the trench structure, a WERR to TOX of1.4 for the regions of the film deposited on the bottom of the trenchstructure, and a WERR to TOX of 1.6 for the vertical regions of the film(sidewall surfaces).

The terms “film” and “thin film” are used herein for simplicity. “Film”and “thin film” are meant to mean any continuous or non-continuousstructures and material deposited by the methods disclosed herein. Forexample, “film” and “thin film” could include 2D materials, nanorods,nanotubes or nanoparticles or even single partial or full molecularlayers or partial or full atomic layers or clusters of atoms and/ormolecules. “Film” and “thin film” may comprise material or layer withpinholes, but still be at least partially continuous.

It will be understood by those of skill in the art that numerous andvarious modifications can be made without departing from the spirit ofthe present invention. The described features, structures,characteristics and precursors can be combined in any suitable manner.Therefore, it should be clearly understood that the forms of the presentinvention are illustrative only and are not intended to limit the scopeof the present invention. All modifications and changes are intended tofall within the scope of the invention, as defined by the appendedclaims.

What is claimed is:
 1. A method of forming a silicon oxycarbonitride(SiOCN) thin film on a substrate in a reaction space by a plasmaenhanced atomic layer deposition (PEALD) process, wherein the PEALDprocess comprises at least one deposition cycle comprising: contacting asurface of the substrate with a vapor phase silicon precursor to therebyadsorb a silicon species on the surface of the substrate; contacting theadsorbed silicon species with at least one reactive species generated byplasma formed from gas that does not comprise oxygen, wherein theadsorbed silicon species is not contacted with oxygen-containingreactive species formed from gas; and optionally repeating thecontacting steps until a SiOCN film of a desired thickness has beenformed; wherein the silicon precursor is selected from the groupconsisting of the following general formulas:(R^(I)O)_(4-x)Si(R^(II)—NH₂)_(x)  (1) wherein x is an integer from 1 to4; R^(I) is independently selected from the group consisting of alkylgroups; and R^(II) is an independently selected from the groupconsisting of hydrocarbon groups;(R^(I)O)₃Si—R^(II)—NH₂  (2) wherein R^(I) is independently selected fromthe group consisting of alkyl groups; and R^(II) is independentlyselected from the group consisting of hydrocarbon groups; and(R^(I)O)_(4-x)Si(—[CH₂]_(n)—NH₂)_(x)  (3) wherein x is an integer from 1to 4; n is an integer from 1-5; and R^(I) is independently selected fromthe group consisting of alkyl groups.
 2. The method of claim 1, whereina ratio of a wet etch rate the SiOCN thin film to a wet etch rate ofthermal silicon oxide is less than about
 5. 3. The method of claim 1,wherein a ratio of a wet etch rate the SiOCN thin film to a wet etchrate of thermal silicon oxide is less than about 0.3.
 4. The method ofclaim 1, wherein a ratio of a wet etch rate the SiOCN thin film to a wetetch rate of thermal silicon oxide is less than about 0.1.
 5. The methodof claim 1, wherein the SiOCN thin film is deposited on athree-dimensional structure on the substrate.
 6. The method of claim 5,wherein a wet etch rate ratio of a wet etch rate of SiOCN formed on atop surface of the three-dimensional structure to a wet etch rate of theSiOCN formed on a sidewall surface of the three-dimensional structure isabout 1:1 in dilute HF.
 7. The method of claim 1, wherein the vaporphase silicon precursor does not comprise a halogen.
 8. The method ofclaim 1, wherein the silicon precursor comprises(3-aminopropyl)trimethoxysilane (APTMS).
 9. The method of claim 1,wherein the reactive species comprises hydrogen plasma, hydrogen atoms,hydrogen radicals, or hydrogen ions.
 10. The method of claim 1, whereinthe reactive species is generated from a second reactant comprising anoble gas.
 11. The method of claim 9, wherein the reactive speciesfurther comprises nitrogen plasma, nitrogen atoms, nitrogen radicals, ornitrogen ions.
 12. The method of claim 1, wherein the reactive speciesis generated by plasma from a second reactant comprising hydrogen. 13.The method of claim 12, wherein the second reactant comprises H₂. 14.The method of claim 1, wherein the SiOCN thin film comprises at least 20at % oxygen.
 15. The method of claim 1, wherein the SiOCN thin filmcomprises at least 5 at % carbon.
 16. The method of claim 1, wherein theSiOCN thin film comprises at least 5 at % nitrogen.
 17. A method offorming a silicon oxycarbonitride (SiOCN) thin film on a substrate in areaction space comprising a plurality of deposition cycles, wherein atleast one deposition cycle comprises: alternately and sequentiallycontacting a surface of the substrate with a silicon precursor and asecond reactant comprising at least one reactive species generated byplasma from gas that does not comprise oxygen, wherein the surface ofthe substrate is not contacted with oxygen-containing reactive speciesgenerated from gas; wherein the deposition cycle is repeated two or moretimes to form the SiOCN thin film; and wherein the silicon precursor hasa general formula:L_(n)Si(OR^(I))_(4-x-y-z-n)(R^(II)NR^(III)R^(IV))_(x)H_(y)(OH)_(z)wherein n is an integer from 0 to 3, x is an integer from 1 to 4, y isan integer from 0 to 3, z is an integer from 0 to 3; and 4-x-y-z-n isfrom 0 to 3; R^(I) is independently selected from the group consistingof alkyl groups; R^(II) is independently selected from the groupconsisting of hydrocarbon groups; R^(III) and R^(IV) are independentlyselected from the group consisting of alkyl groups and hydrogen; and Lis independently selected from the group consisting of alkyl groups andhalogens.
 18. The method of claim 17, wherein the silicon precursor hasa general formula:L_(n)Si(OR^(I))_(4-x-n)(R^(II)NR^(III)R^(IV))_(x) wherein n is aninteger from 0 to 3, x is an integer from 1 to 3; L is independentlyselected from the group consisting of alkyl groups and halogens; R^(I)is independently selected from the group consisting of alkyl groups;R^(II) is independently selected from the group consisting ofhydrocarbon groups; and R^(III) and R^(IV) are independently selectedfrom the group consisting of alkyl groups and hydrogen.
 19. The methodof claim 17, wherein the silicon precursor has a general formula:Si(OR^(I))_(4-x-y-z)(R^(II)NR^(III)R^(IV))_(x)H_(y)(OH)_(z) wherein x isan integer from 1 to 4, y is an integer from 0 to 3, z is an integerfrom 0 to 3; R^(I) is independently selected from the group consistingof alkyl groups; R^(II) is independently selected from the groupconsisting of hydrocarbon groups; and R^(III) and R^(IV) areindependently selected from the group consisting of alkyl and hydrogen.20. The method of claim 17, wherein the silicon precursor has a generalformula:Si(OR^(I))_(4-x)(R^(II)NR^(III)R^(IV))_(x) wherein x is an integer from1 to 4; R^(I) is independently selected from the group consisting ofalkyl groups; R^(II) is independently selected from the group consistingof hydrocarbon groups; and R_(III) and R_(IV) are independently selectedfrom the group consisting of alkyl groups and hydrogen.
 21. The methodof claim 17, wherein the silicon precursor comprises APTMS.
 22. Themethod of claim 17, wherein at least one deposition cycle is a PEALDcycle.
 23. The method of claim 17, wherein a reactive species isgenerated by applying RF power of 100 Watts (W) to about 1000 W to thesecond reactant.
 24. The method of claim 17, wherein the depositioncycle is carried out at a process temperature of about 300° C. to about400° C.
 25. The method of claim 17, wherein the deposition cycle iscarried out at a process temperature of less than about 100° C.
 26. Themethod of claim 17, wherein the substrate comprises an organic material.27. A method for depositing a silicon oxycarbonitride (SiOCN) thin filmon a substrate in a reaction space comprising: contacting a surface ofthe substrate with a silicon precursor comprising; at least one ligandbonded through carbon to a silicon atom and containing an NH₂-groupattached to a carbon chain; and at least one ligand bonded to thesilicon atom through an oxygen atom and in which an alkyl group isbonded to the oxygen atom; exposing the substrate to a purge gas and/orvacuum to remove excess silicon precursor and reaction byproducts, ifany; contacting a surface of the substrate with a second reactantcomprising hydrogen, wherein the second reactant comprises at least onereactive species generated by plasma and wherein surface of thesubstrate is not contacted with oxygen-containing reactive speciesgenerated from gas; exposing the substrate to a purge gas and/or vacuumto remove excess second reactant and reaction byproducts, if any;repeating the contacting steps until a SiOCN thin film of desiredthickness has been formed.